1995 cheverlot Camaro

I have a 1995 cheverlot camaro, 3.4L engine, 140,000 miles, auto matic, tilt steering. The ignition switch cylinder will turn, but the car will not crank. The battery has the proper voltage, the headlights, interior ights, tail lights, seats, mirrors, door locks, and hazard lights works. Everything that needs to work with the key doesn't. Will not crank, windows will not work, radio doesn't work. Is there an electrical problem with the cars computer, or is the problem with the ignition switch? All the fuses have been checked and are good. Please help.